Importance: Maximizing benefits of lung cancer screening requires timely follow-up after a positive screening test. The American College of Radiology (ACR) Lung CT Screening Reporting and Data System (Lung-RADS) recommends testing and follow-up timing based on the screening result.
Objective: To determine rates of and factors associated with recommended follow-up after a positive lung cancer screening examination by Lung-RADS category.
Design, setting, and participants: This prospective cohort study of lung cancer screening examinations performed from January 1, 2015, through July 31, 2020, with follow-up through July 31, 2021, was conducted at 5 academic and community lung cancer screening sites in North Carolina. Participants included 685 adults with a positive screening examination, Lung-RADS categories 3, 4A, 4B, or 4X. Statistical analysis was performed from December 2020 to March 2022.
Exposures: Individual age, race, sex, smoking exposure, year of lung cancer screening examination, chronic obstructive pulmonary disease, body mass index, referring clinician specialty, rural or urban residence.
Main outcomes and measures: Adherence, defined as receipt of recommended follow-up test or procedure after the positive screen per ACR Lung-RADS timeframes: 6 months for Lung-RADS 3 and 3 months for Lung-RADS 4A. For Lung-RADS 4B or 4X, adherence was defined as follow-up care within 4 weeks, as ACR Lung-RADS does not specify a timeframe.
Results: Among the 685 individuals included in this study who underwent lung cancer screening with low-dose computed tomography, 416 (60.7%) were aged at least 65 years, 123 (18.0%) were Black, 562 (82.0%) were White, and 352 (51.4%) were male. Overall adherence to recommended follow-up was 42.6% (292 of 685) and varied by Lung-RADS category: Lung-RADS 3 = 30.0% (109 of 363), Lung-RADS 4A = 49.5% (96 of 194), Lung-RADS 4B or 4X = 68.0% (87 of 128). Extending the follow-up time increased adherence: Lung-RADS 3 = 68.6% (249 of 363) within 9 months, Lung-RADS 4A = 77.3% (150 of 194) within 5 months, and Lung-RADS 4B or 4X = 80.5% (103 of 128) within 62 days. For Lung-RADS 3, recommended follow-up was less likely among those currently smoking vs those who quit (adjusted odds ratio [aOR], 0.48; 95% CI, 0.29-0.78). In Lung-RADS 4A, recommended follow-up was less likely in Black individuals vs White individuals (aOR, 0.35; 95% CI, 0.15-0.86). For Lung-RADS 4B or 4X, recommended follow-up was more likely in female individuals vs male individuals (aOR, 2.82; 95% CI, 1.09-7.28) and less likely in those currently smoking vs those who quit (aOR, 0.31; 95% CI, 0.12-0.80).
Conclusions and relevance: In this cohort study, adherence to recommended follow-up after a positive screening examination was low but improved among nodules with a higher suspicion of cancer and after extending the follow-up timeline. However, the association of extending the follow-up time of screen-detected nodules with outcomes at the population level, outside of a clinical trial, is unknown. These findings suggest that studies to understand why recommended follow-up is lower in Black individuals, male individuals, and individuals currently smoking are needed to develop strategies to improve adherence.